More than 287,000 users have already signed up for the event, with another 313,000 expressing interest in attending.

“We will all meet up at the Area 51 Alien Center tourist attraction and coordinate our entry,” the group’s organizer wrote. He suggests that if everyone runs head-long at the base, “we can move faster than their bullets.”

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The Area 51 raid is set to be held at 3 a.m. on Sept. 20.

“Let’s see them aliens,” the group description says.

The event appears to be a massive inside joke, with thousands of users posting tongue-in-cheek plans of attack on the discussion page.

Some joked about how quickly the U.S. military would be able to stop the raid. Others quipped about sponsorship plans, catering and which bands would be playing the event.

Several people shared memes comparing the so-called “invasion” to the massive superhero fight at the end of the Marvel film Avengers: Endgame.

“Whatever it takes,” they wrote, quoting the film.

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Area 51 is a U.S. Air Force facility located in a restricted area some 135 kilometres north of Las Vegas. It’s been a military testing ground for more than 60 years and played an important role in developing stealth-fighter technology for the U.S. military.

It’s also a focal point for many conspiracy theories that suggest it’s a site for alien autopsies and testing UFO-inspired technologies.

The CIA acknowledged the site’s existence in 2013 when it declassified a vast trove of top-secret documents compiled during the Cold War. However, the documents failed to satisfy the tinfoil-hat crowd, as they did not contain any information about aliens or UFOs.

Warning signs at the restricted boundary to Area 51 on an unmarked dirt road near the town of Rachel and the UFO Highway.

CP PHOTO/Larry MacDougal

The Pentagon has previously confirmed that the U.S. government ran a $22-million program to investigate reported UFO sightings. The program started in 2007 and ended in 2012.

“It was determined that there were other, higher priorities that merited funding and it was in the best interest of the DoD to make a change,” a Pentagon spokesperson said at the time.